Kiln



R. c. PURDY.

KILN.

APPLICATION FILED JUNE I5, 1918.

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R. C. PURDY.

KILN.

APPLICATION FILED JUNE I5, ISIS.

1,332,471. Patented Mar. 2, 1920.

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Anm/5555 nvr/EN 70H CLAUDEEKLUND /QOSSCPQ/QDY UNITED STATES PATENT' OFFICE. i

Boss c. PUNDY, OF WORCESTER., MASSACHUSETTS, AssvIGNOn TO NORTON COMPANY, A

c CORPORATION OF MASSACHUSETTS.

' KILN.

A Speclcation of Letters Patent.

Patented Mar. 2, 1920.

Application led June 16, 1918. Serial No. 240,194.-

Kilns, of which the following is a full, clear,

and exact specification.

` My invention relates to kilns and particularly to the Hue system of the up and down draft and reversible draft type kilns for burning pottery, grinding wheels, electrical insulators and other ceramic wares that are placed in saggars for burning. v

Where the total output of a Jfactory will not warrant the operation of a kiln of the tunnel type or multiple chambers as in the so-called continuous kiln, or in such manufacturing operations where the nature of the ware requires the use of so-called periodic or individual kilns, eiiiciency and economy i of plant operation require the use of the largest kiln possible.

The only limitation to the size of the periodic kilns is even heat distribution throughout the kiln, which is necessary for the production of a uniformly standard product. In most kilns the temperature varies from the top or crown of the kiln to the iooror bottom and also varies fro-m the outside circumference to the center, and as this variation in heat distribution in different parts of the kiln differs' in kilns even though of like design, and under the several varying conditions attending the burning of a single kiln, it has been the aim of kiln designers to reduce the liability of such variation in heat treatment as much as possible.

The advantages of the larger kilns as compared with the smaller kilns, if the larger ones can be burned with as even a heat distribution, are quite obvious: (l) the capacity of a kiln is increased rapidly with increase in diameter, thus saving factory floor space and increasing the capacity of a plant: (2) the repair costs are materially reduced per ton or per value of ware: (3) the number of kiln firemen and attendants per plant capacity is decreased: (4:) the wholeoperation of kilns, including the drawing, setting and burning of the ware is much simplified as well as made more economical, and (5) if the flue systems are properly designed and proportioned it is possible to burn -large kilns in the same number of hours as is required for the smaller kilns.

The advantages of the smaller kilns are the smaller number of hours required for b urning and cooling, thus affording the possibility of reducing the time of manufacturing for a given lot of ware. This advantage of the smaller kilns, the use of shorter burn- -ing and cooling time, would be considerably reduced if the fines were so designed and proportioned as to give better heat distribution.y

It is accordingly an object of my invention to obvlate the disadvantages previously considered inherent in the large sized kilns and to improve the construction of kilns of all sizes by providing an eiiicient arrangement of flues therein properly designed and proportioned to give uniform heat distribution throughout the whole kiln interior, whereby ceramic articles in all parts of the kiln may receive the same heat treatment.

With this and other objects in view, as will be apparent from the folowing disclosure, my invention resides in the combination of parts set forth in the specification and described in the claims appended hereto.

In the drawings, in which like reference numerals indicate like parts Figure l is a sectional elevation, partly broken away, of a kiln embodying my invention; and

Fig. 2 is a sectional view, partly' broken away, on the line 2-2 of Fig. l, showing the arrangement of inlet and outlet flues above and below the floor of the kiln.

As a specific embodiment of my invention, I have illustrated a kiln construction built of suitable materials, such as fire brick, etc., forming a' cylindrically shaped heating chamber l connected with coal-burning fire boxes 2 or other suitable sources of heat disposed at intervals around the exterior walls of the kiln, adjacent to the base thereof. Spaced above the ioor 3 on which the articles to be burned are placed is an arched vroof or crown 4c adapted to reflect the heat stacks and in turn reducing the fire hazard to the factory buildings. The floor 3 is supported by a series of spaced walls 8 whlch form and deine the various inlet and outlet conduits through which the gases pass to and from the heating chamber.

In order that the kilns may be heated evenly and efficiently, I have devised a special arrancement of 'lues and passages as illustrated. lach fire box 2 is connected with the heating chamber by a multiple flue 9, of such a size in cross-sectlon and so arran ed as to heat the kiln uniformly. A conduit or stack 10, supported on the kiln foundation and passing through the ioor at the center of the kiln, serves to create draft necessary to some of the combustion gases from the fire boxes and to so distribute the gases as to equalize the temperature throughout the heating chamber. This stack pro-r jects considerably above the iioor to prevent gas creepingalong) the floor to an outlet opening therein. penmgs 11 are provided in the lower portion of the wall of this stack for the passage of gases from the flues 9. Since one ire box may give more heat than 'another or unequal draft conditions otherwise tend to prevail, I provide an annular gas-mixing room 13 around the stack 10 by stopping the radial outlet flue walls short of the stack. Each flue 9 opens into this annular passage 13 and the latter in turn opens into the stack 10 through the openings 11. By this construction the gases coming from the different iues tend to circulate around the baile wall formed by the stack in their effort to go. through the openings 11. Therefore the heated gas coming into the kiln at the center is of uniform temperature and not made up of different currents of relatively cold and warm gases.

The other kinlet for the combustion gas into the kiln interior comprisesnan opening 15 direct from the fire box, this opening being adjacent to the peripheral wall of the heating chamber. This opening 15 leads to `a passage within a vertically disposed bag wall or stack 16 which isopen at the top 17 and has spaced openings 18 in its side walls, whereby the gas may issue not only through the top of -this passage but through the side walls toward the ceramic material packed on the floor of the kiln.

Due to the large area of the kiln ioor and the fact that the fire boxes are spaced 'apart by a considerable distance, there are large masses of supporting walls 8 beneath the ioor, between the flues, which would be relatively cold and so affect the temperature of the floor unless this condition be obviated.`

I overcome this tendencyl by breaking up the construction beneath the flooring so as to 'form a plurality of heated passages through the brickwork. To this end I form main passages 20 through openlngs 26 and 27, are provided to 'heat the floor-supporting brlckwork at the outer portions of the kiln. Each pair of lues forming a multiple flue 9 draws exclusively from a single re box and discharges the gases into the annular gasmixing room 13, thus obviatin the disadvantages of the usual constructlon whereby the -lues which` discharges into the center well pit draw from two fire boxes.

To provide for the exhaust or escape of gases from the kiln interior, I provide outlet flues 28 radially-disposed between the inlet passages. Adjacent columns'deiining flues 23 from pairs of lire boxes are brought together at 29 to form the outer wall `portions of the gas-mixing room 13 and to provide a closed end 'for the outlet passage between parallel walls 30. This arrangement of outlet conduit walls permits a complete separation of the inlet conduits of adjacent fire boxes so that the gas from one lire box.

cannot mix with the gas from another until the annular mixing room is reached, whereby any interference with the draft of one fire box by its neighbor is obviated.

The gas exit from the heating chamber is by way 'of spaced openings 31 in the floor over the outlets 28,`these openings preferably increasing in sizetoward the center of the kiln to prevent the draft short-circuiting from the passages 15 to the outlets. The innermost ioor opening, by this arrangement of flue walls, is located nearer the kiln center than heretofore possible in other constructions and thereby materially vincreases the activity of the draft. and brings more heat to the kiln center. The outlet passages these in turn communicating at their upper ends with `the large chimney space above the crown 4, so thatgases passing out through the chimney flues may escape to the open alr.

I furthermore construct these passages so that the gas is not held back by constrictions at any point, by providing that the crosssectional areas o'f the inlet ues 20 are alike and uniform throughout, and that the passages 23 are! su'iciently large to accommodate all the gases coming from the smaller channels 20, this being accomplished by mak ing the flue 23 deeper than passages 20. An opening 33 is provided in the top of the crown and a cover 34 provided therefor, So

that/,during the starting of the kiln the may be allowed to ass directly outthrou h the chimney, and t ereby aior'd a more irect' draft. This cover 1s, however, placed over the opening dur' the actual burnin of the ceramic ware sdnlat the gas is force to travel circuitously as previously described.

The operation of thekiln is obvious from the above, disclosure. The gases y coming from the fire boxes 2 pass both through the opening 15 into the peripheral portion of the kiln and along the passages comprising the inlet lues 9 to the gas-mixing passage 13 and the centrally located stack', and then into the interior ot the kiln. After ,circulating through the heating chamber 1 these gases ass downwardly through the openings 31 into the radially disposed outlet conduit 28 and then into the vertical ilues 32 and up the chimney.

By this arrangement of dues, l insure an even heating of the kiln and an economical use of the heating fuel, because the passages are so proportioned and shaped that the gases must mix before entering the heating chamber and must divide -in `correct proportions between the inlet stacks 10 and 16. l furthermore. provide a construction which not only makes possible the use of larger kilns than'heretofore thought pomible but 1ncreases the efficiency of small sized kilns.

Having thus described my invention, what l claim as new and desi-re to secure by Letters Patent is:

1. A ceramic kiln comprising walls dehning the sides, top and floor of a heating chamber and aplurality of inlet dues beneath the door, :lire boxes adjacent the exterior of the chamber opening into said dues, a bao wall opposite the em'ts of adjacent fines forming a room wherein the gases cominn` from several ire boxes are mixed, a conduit pipe from said room to the exterior ot the heating chamber above the Vfloor and means for exhausting the gases from the heating chamber.

A 2. A ceramic kiln comprising walls forming a heating chamber for articles to be burned, a ooring therefonre boxes adj acent the emerior thereof, a centrally `located vertical conduit extending and opening beneath and above the door of the heating chamber for the passage of as, lwalls forming inlet fines beneath the ooring connecting said fire 'boxes with an annular gas-mixing room around and communicating with the conduit and means providing a gas outlet Jfrom the heating chamber.

3. ln a ceramic kiln, walls forming a heating chamber, a iioor therefor, iire boxes peripherally disposed about the chamber, a centrally disposed stack opening aboveand beneath the floor, walls separating the rire boxes and extendinginwardly to positions spaced ciroumferentially about the stack, i)

ereby formin multi le'radial'inlet lues from each re x, an a gasmixing room about and communicating with the stack beneath the ioor, bag walls providing a se arate openin from each iiue to the heatlng chamber adjacent the peripheral wall thereof and means providing a gas outlet through the floor to 'a chimney opening to the atmosphere. Y

4. In a ceramic kiln, walls forming a heat- 'ing chamber, a floor therefor, fire boxes disposed about the (periphery of thecha'mber, a centrally locate stack projecting throu h the floor and havin an opening intot e heating chamber, an one beneath the floor,- inlet walls supporting' the Hoor and for iiues com rising a plurality of substantiall radially isposed passages connecting eac lire box with a single large assage of a gascarrying capacity equal to that of the several passages, said walls stopping short of the stack to form an annular room thereabout for receiving gases from the large passage of each inlet flue and distributing them to the stack opening, walls forming radially disposed outlet iiues beneath the door which has `openings therethrough to said dues and means for carrying gases therefrom to the atmosphere 5. ln a kiln comprising walls inclosing a heating chamber for .the objects to be burned and tire boxes arranged circumerentially about the kiln, the combination with a iloor for the heating chamber having` inlet and outlet openings therein, of due walls beneath the door forming radially disposed, unconstricted flues from said iire boxes to said inlet openings alternating with outlet conduits from the chamber, said walls terminating at a distance :from said center so as to form a gas-mixing room, a centrally located, open-topped stack projecting from the kiln base tl'irough 'the floor and having spaced openings communicating with said mixing room, a perforated bag wall above the door? and'dening a conduit opening from the inlet due ot .ea-ch iireb-ox to the heating chamber adjacent the peripheral wall of the kiln, and a chimney surmounting the kiln-heating chamber, the kiln walls having vertical iiues therein connecting the radially disposed outlet conduits withthe chimney to provide a dra for the :lire boxes.

6. A ceramic kiln comprising walls deiining a heating chamber, iire boxes around the periphery of the chamber, walls forming sets of radially disposed, multiple inlet iues, each set comprising a plurality of passages drawing from a single re box, a baffle wall opposite the exits of saidues defining a gas-mixing-room, walls forming a separate communicating passage from each set of rio " 7. A-'oeramc kiln comprising sides, l top and Hoor, of al ing' thev halnber, fire the chamber, ing ses,

Y jues having' unrestricted ewch set drawing so ely from one fire' l box, outlet 'e walls radially disposed between heating and meansfor L exhausting gases from the'latter.

walls definboxes varoundl the periphery of wells `beneath the floor defindisposed, multiple inlet of radially assages of `equal flues,

'13th day of June, 1918. the inlet f lues and terminating. neer v y the center of the kiln to; form al periphersh concentric within said tllerewitli a room, vseid 'inlet des discharg- --mginto said room through the `ripheral wall and floor being provided with openings into the inner ,ends ofthe outlet a. gas conduitand means to exhaust the gases from 'the outlet lines.

Signed at Worcester,

Ross 3C.- PURDY.

Massachusetts, this 

